Plant parasitic nematodes in new jersey.

the number of bacteria per dauerjuvenile. Preliminary data established similar LD50s and LT50s for X. nematophilus subsp, nematophilus (from the DD 136 strain) and X. nematophilus subsp, nematophilus vat. mexicanus (from the Mexican strain). The absence of toxin production by either S.feltiae strain or bacterial types in a culture medium similar to the host's hemolymph has been reported (5,6). Thus behavioral differences or differences in the number of bacteria per dauer juvenile may account for differences in virulence between the S. feltiae strains. In the present study, differences in virulence were influenced by temperature. Although the rasping denticle of H. heliothidis, which is not present in steinernematids, may account for the accelerated kill rate by the heterorhabditid (2), T. A. Rutherford (pers. comm.) has observed that steinernematid dauerjuveniles kill Tenebrio molitor larvae faster than do the heterorhabditids.